For most Infiniti G37 owners, replacing the serpentine belt typically costs roughly $120–$260 if you replace only the belt, and $250–$600 if the tensioner or idler pulleys are also replaced. Dealer quotes tend to be higher, while independent shops are usually on the lower end.
The Infiniti G37 uses a 3.7-liter V6 engine with a single serpentine belt that drives accessories such as the alternator, power steering, and AC compressor. Over time the belt wears, cracks, or stretches, and the tensioner or idler pulleys can wear as well. Prices vary by region, shop, and whether OEM or aftermarket parts are used.
Cost breakdown
Below is a typical price breakdown for a serpentine belt replacement on the G37. It distinguishes belt-only replacement from a belt replacement that includes the tensioner or idlers.
Parts and labor components
- Serpentine belt (OEM or aftermarket): often $25–$90
- Belt tensioner (if replaced): $60–$180
- Idler pulley(s) (if replaced): $20–$80 each
- Labor to replace belt: roughly 0.5–2 hours at shop rate (commonly $75–$150/hr)
In practice, most belt-only jobs fall in the $120–$260 range. If the tensioner and/or idlers are replaced during the service, total costs typically rise to the $250–$600 range depending on parts and labor rates.
What factors influence the price
Prices vary based on where you go and what you replace. The following factors often determine the final bill.
Shop type and region
- Independent repair shops generally charge less than dealerships
- Labor rates vary by region; urban areas tend to be higher
Keep in mind that the region and shop type are usually the biggest drivers of final price.
What’s being replaced
- Only belt vs. belt plus tensioner and/or idlers
- Brand choice (OEM vs. aftermarket) can affect belt and tensioner prices
Replacing more components adds to the cost, but can prevent future failures and save labor on a second visit.
Vehicle condition and access
- Vehicle accessibility and complexity affect labor time
- Extra labor may be needed for difficult-to-reach pulleys
Complex access or extra tasks can push labor time toward the higher end of the range.
Tips to save money
Shop around, consider the value of bundled parts, and plan for the service alongside other maintenance to save on labor. The following tips can help reduce the cost.
- Ask for a belt-only replacement if diagnostics show the tensioner is in good condition
- Get quotes from multiple shops, including independent mechanics
- Consider aftermarket belts from reputable brands if you’re not chasing OEM parts
- Combine maintenance tasks during a single visit to reduce overall labor time
Doing your homework can lead to meaningful savings without compromising reliability.
Summary
Replacing a serpentine belt on a G37 is a straightforward service with costs mainly driven by parts selection and labor rates. Expect $120–$260 for belt-only replacements, and $250–$600 when the tensioner and/or idlers are replaced. Always compare quotes from a few shops, and consider whether replacing the tensioner or idlers now might save on future labor costs. Regular inspection can catch wear before it fails and keep the accessories running smoothly.